Ryuji Sasai (笹井隆司, Sasai Ryūji, born December 21, 1961) is a Japanese former video game composer and bass guitarist. He is best known for his work on Xak, Final Fantasy Legend III and Final Fantasy Mystic Quest. Sasai is well-known for his rock style. His musical career came about when he was 15 years old, and he formed a band. Before entering the gaming industry, Sasai was involved in the anime department, scoring two television series and a film. After creating music for four games as a freelancer, he was employed at Square from 1991 to 1998, where he worked on five games in total.
Sasai often collaborated with fellow composers Tadahiro Nitta and Chihiro Fujioka during his career. He has also been a member of the rock bands Novela and Action and is currently performing as a bassist.